[DirtyHarrySW29]

Most of your gun steel is 4140 if I’m correct. Why couldn’t a better alloy like some cobalt steel be used since it’s so much more heat resistant.

 

[Layne12gun]

to hard to rifle the barrels . Heat is not a problem!! longivity of the barrel ## of Rounds is along with accuracy

 

[Smith Shooter]

Machining difficulty and tool wear would be major problems for little to no benefit.

 

[delcrossv]

There's been some work done with maraging alloys, mostly for the military.

 

[DirtyHarrySW29]

There's been some work done with maraging alloys, mostly for the military.

now I’m not familiar with that alloy, what alloy is it?

 

[delcrossv]

now I’m not familiar with that alloy, what alloy is it?

Very low carbon martensitic steels. More like a nickel-iron alloy.
"Maraging steel contains an extremely low amount of carbon (0.03% maximum) and a large amount of nickel (17—19%) together with lesser amounts of cobalt (8—12%), molybdenum (3—5%), titanium (0.2—1.8%) and aluminium (0.1—0.15%). Maraging steel is essentially free of carbon, which distinguishes it from other types of steel."

https://www.sciencedirect.com/topics/materials-science/maraging-steel

E.g.C-250, Maraging 300, etc.